Should international borders re-open? The impact of travel restrictions on COVID-19 importation risk

Abstract

Background Novel coronavirus disease (COVID-19) has spread across the world at an unprecedented pace, reaching over 200 countries and territories in less than three months. In response, many governments denied entry to travellers arriving from various countries affected by the virus. While several industries continue to experience economic losses due to the imposed interventions, it is unclear whether the different travel restrictions were successful in reducing COVID-19 importations. Methods Here we develop a comprehensive probabilistic framework to model daily COVID-19 importations, considering different travel bans. We quantify the temporal effects of the restrictions and elucidate the relationship between incidence rates in other countries, travel flows and the expected number of importations into the country under investigation. Results As a cases study, we evaluate the travel bans enforced by the Australian government. We find that international travel bans in Australia lowered COVID-19 importations by 87.68% (83.39 - 91.35) between January and June 2020. The presented framework can further be used to gain insights into how many importations to expect should borders re-open. Conclusions While travel bans lowered the number of COVID-19 importations overall, the effectiveness of bans on individual countries varies widely and directly depends on the change in behaviour in returning residents and citizens. Authorities may consider the presented information when planning a phased re-opening of international borders.

A measure to estimate the risk of imported COVID-19 cases and its application for evaluating travel-related control measures

“…Real-time travel volume, the numbers of cases in the source countries, and the ability to detect cases (i.e., surveillance capacity) should be considered in estimating the risk of travel-associated COVID-19. Travel volume is obviously related to imported cases, and the number of cases and surveillance capacity combined reflect the true size of the pandemic in the source countries 7 . Although several studies have estimated importation risks 8 – 14 , none of these used real-time travel data.…”

Effects of COVID-19 pandemic on education and society

“…In [36], it has been reported that this situation affects not only prospective international students, but also international students who are already in the host countries and are obligated to prove that they have sufficient resources to support themselves throughout their studies. (iii) Nations across the globe closed international borders to mitigate the outbreak [37]. Educational authorities across the world were asking their international students not to travel overseas, or even to return to their country of origin, as they may put themselves at high risk of getting infected.…”

Global border restrictions in 2020–2021: Adherence and the effectiveness in long-term COVID-19 epidemic control

“…However, there remained many knowledge gaps and arguments about whether implementing border policies were useful in the overall epidemic control. To be specific, border restrictions were once identified effective in suppressing early COVID-19 epidemics [ 18 , 19 ], whereas they were considered ineffective in regions where there already existed severe community spreads [ [20] , [21] , [22] ], implicating that conclusions may vary in different timings of observations. In fact, since outbreaks usually precede the adoption of border policies, previous observational studies performing in relatively short-term (Ranged form 14–153 days.…”